Rectangular container having inset label panels and concave heel geometry

ABSTRACT

A rectangular plastic container formed by blow molding includes an upper portion, an upper label bumper, a base portion having a heel that curves inward to meet a standing edge at a bottom of the container, and a lower label bumper. The container further includes a body portion disposed between the upper portion and the base portion. The body portion includes front, back, and side label panel areas meeting at rounded corner regions of the body portion. The label panels each having a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion. The front and the back label panel areas are inset from the upper bumper by a distance which is greater than an inset distance of the side label panel areas with respect to the upper bumper.

BACKGROUND

1. Technical Field

This invention generally relates to containers for holding beverages orother liquids or food products. More specifically, this inventionrelates to rectangular containers having inset label panels and concaveheel geometry.

2. Related Art

Plastic containers, such as those made of polyethylene terephthalate(PET), are widely used for packaging liquid and food products. Suchcontainers may be formed using a blow molding process, in which apreform is filled with gas until it fills the interior of a mold havingthe desired shape of the container. During a stretch blow moldingprocess, for example, the preform is first stretched mechanically with astretch rod, and as the rod is extended, low-pressure air is introducedto blow an air bubble in the preform. Once the stretch rod is fullyextended, high-pressure air is used to blow the expanded preform intothe shape of the mold.

Perishable foods, such as juices and soup, are often filled at anelevated temperature, in a process generally referred to as “hot-fill.”In a typical hot-fill process, a liquid or flowable product is chargedinto a container at elevated temperature, such as 180 to 190° F., underapproximately atmospheric pressure, and the container is hermeticallysealed using a closure, such as a cap. Upon subsequent cooling of thecontents, a vacuum forms within the container due to shrinkage of thecontents. By contrast, in a “cold-fill” process, the product is chargedinto a container approximately at a room temperature under atmosphericpressure, so a vacuum condition does not occur in the container.

Hot-fill containers typically are designed with vacuum panels formed inthe container sidewall that flex in response to a decrease in internalpressure. For example, some plastic containers have several,equidistantly spaced vacuum panels that are configured to enable acircular label to be wrapped around the container. Land areas betweenthe panels provide surfaces around which the label may be applied.Inward flexing of the vacuum panels in response to vacuum pressureprevent severe distortion of the land areas. Other plastic containersare configured to have opposing hand-grips that flex to absorb theinternal vacuum. Flexing of the hand-grips in response to internalnegative pressure prevents severe distortion of the surfaces to thefront and to the rear of the hand-grips, which can receive labels.

While container designs relying on vacuum panels have been effective,certain limitations and disadvantages are associated with their use,including limitations as to the possible variations in the exteriorstyling of the container, the need to provide enough plastic material toform the vacuum panels with the requisite thickness, and incompatibilitywith certain types of package labeling processes. For example, it isdifficult to use certain types of pressure sensitive labeling onhot-fill containers that have prominent vacuum panels.

In addition, while hot-fill containers are designed to withstandinternal vacuum conditions, the containers are sometimes subjected topositive internal pressure during the filling process. For example, somefilling equipment subjects the container to internal positive pressurefor a brief period. Containers having long stiffening ribs or other longstiff structures may, in response to positive internal pressure, locallybulge outwardly in a kink. Such a kink might remain even after thecontainer encounters internal vacuum, or the kink may disappear butleave a wrinkle in the wall of the container. Kinks and wrinkles make acontainer unappealing and are considered to be commercially undesirable.

Many existing containers have a large grip portion at the top of thecontainer with large indented grip areas or handles. Such configurationsrequire the label panel to be located below the grip area toward thebottom of the container elevation. This is commercially undesirable,because the product label tends to have better visibility when it islocated in the middle or upper portion of the container elevation.

In rectangular blow-molded containers (including square containers), thecorners of the heel portion tend to be more susceptible to damage,because they project from the bottom surface of the container and arelikely to receive an impact force if the container is dropped. Moreover,the corners are formed of material that is stretched more than any otherportion of the container during the blow molding process, i.e., becausethe bottom corners of the container are the greatest distance from theinitial position of the material of the preform. Thus, the corners mayhave the thinnest wall thickness of any portion of the container, whichmakes deformation of or damage to these portions more likely.

SUMMARY

In one aspect, the present invention provides a rectangular plasticcontainer formed by blow molding. The container includes an upperportion having a finish at the top for receiving a closure, an upperlabel bumper extending around a periphery of the container at a bottomof the upper portion, a base portion having a heel that curves inward tomeet a standing edge at a bottom of the container, and a lower labelbumper extending around the periphery of the container at a top of thebase portion. The container further includes a body portion disposedbetween the upper portion and the base portion. The body portionincludes front, back, and side label panel areas that meet at roundedcorner regions of the body portion. The label panels each have aplurality of horizontal ribs, each horizontal rib having four portionsseparated by gaps, such that each of the four portions extends into thecorner regions of the body portion. The front and the back label panelareas are inset from the upper bumper by a distance which is greaterthan an inset distance of the side label panel areas with respect to theupper bumper.

In another aspect, the present invention provides a rectangular plasticcontainer formed by blow molding that includes an upper portion having afinish at the top for receiving a closure, an upper label bumperextending around a periphery of the container at a bottom of the upperportion, a base portion having a heel that curves inward to meet astanding edge at a bottom of the container, and a lower label bumperextending around the periphery of the container at a top of the baseportion. The container further includes a body portion disposed betweenthe upper portion and the base portion. The body portion includingfront, back, and side label panel areas. The heel includes indentedportions at corners thereof. The indented portions have a depth thatgradually decreases with increasing elevation, so that the indentedportions merge with the surface of the base at a top portion of thebase.

In another aspect, the present invention provides a rectangular plasticcontainer formed by blow molding that includes an upper portion having afinish at the top for receiving a closure, an upper label bumperextending around a periphery of the container at a bottom of the upperportion, a base portion having a heel that curves inward to meet astanding edge at a bottom of the container, and a lower label bumperextending around the periphery of the container at a top of the baseportion. The container further includes a body portion disposed betweenthe upper portion and the base portion. The body portion has front,back, and side label panel areas that meet at rounded corner regions ofthe body portion. The label panels each have a plurality of horizontalribs, each horizontal rib having four portions separated by gaps, suchthat each of the four portions extends into the corner regions of thebody portion. For each rib, the gap between the portions of the rib isbetween 0% and about 7% of the circumference of the container at theelevation of the rib.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a rectangular container inaccordance with the present invention.

FIG. 2 is a front elevation view of the rectangular container.

FIG. 3 is a side elevation view of the rectangular container.

FIGS. 4A-B are cross-section views of different parts of the bodyportion of the rectangular container, as indicated in FIG. 2.

FIG. 5 is a bottom view of the rectangular container.

FIG. 6 is a bottom perspective view of the rectangular container.

FIG. 7 is another front elevation view of the rectangular container.

FIGS. 8A-D are cross-section views at different elevations of the heel,as indicated in FIG. 7, showing the change in shape of the indentedportions of the heel.

FIG. 9 is a cross-section view of the rectangular container at line8C-8C in FIG. 7, showing dimensional references for defining the shapeof the indented portions of the heel.

DETAILED DESCRIPTION

FIGS. 1-3 show a plastic rectangular container 10, which may be, forexample, formed of polyethylene terephthalate (PET) in a blow moldingprocess. The container also may be formed of other materials, such as,for example, polybutylene terephthalate (PBT), polyethylene naphthalate(PEN), or a blend comprising the same. The container 10 is suitable forhot-fill processes, in which the container is filled with product at anelevated temperature, capped, and allowed to cool. The container 10 isalso suitable for cold-fill processes, in which the container is filledwith product at or near room temperature.

The container 10 has a body portion 6 that forms the central portion ofthe container and a rounded upper portion 4 that forms the top of thecontainer. A finish 2 extends from the top of the upper portion 4 andincludes a threaded portion for receiving a threaded closure (notshown). The body portion 6 has sidewalls 14 that provide front, back,and side label panel areas for the attachment of a label, e.g., apressure-sensitive label.

Below the body portion 6 is a base portion 8 that forms the bottom ofthe container. The base portion 8 has a tapered portion, referred to asthe heel 22. At the bottom of the container 10, there is a substantiallyplanar standing edge 26, which allows the container to stand on a flatsurface. The base portion 8 also has a reentrant portion 32 that extendsup into the middle of the bottom of the container (see FIGS. 5 and 6),such that the standing edge 26 extends around the periphery of thereentrant portion 32.

Each of the label panel areas of the body portion 6 has a number ofhorizontal ribs 19 to provide increased strength to the sidewalls 14.Unlike conventional container designs, the horizontal ribs 19 are notcontinuous around the periphery of the container. Rather, the ribs 19extend into the corner portions of the sidewalls 14, but do not extendall the way around the corner portions, such that there are gaps in theribs 19 in the corner portions of the sidewalls. Thus, each rib 19 hasseparate portions (four portions in this case) that end in the cornerportions of the sidewalls 14.

These discontinuous horizontal ribs 19 act to strengthen each of thelabel panel areas of the sidewalls 14 to prevent flexure within thelabel panel areas, while allowing flexure at the corners. Thus, thecorners, in effect, operate as hinges. This configuration allowsinternal and external forces to be at least partially dissipated throughflexure of the corner portions, thus preventing undesirable flexure ofthe label panel areas. It should be noted that the separate portions ofeach rib 19 may actually meet at the corner (i.e., have a gap of zero),but the rib portions have no depth at this meeting point and thereforestill allow hinge-like bending to occur at the corner.

As shown in FIGS. 2 and 3, an upper label bumper 16 extends around theperiphery of the container at the bottom of the upper portion 4, and alower label bumper 23 extends around the periphery of the container atthe top of the base portion 8. The bumpers (16 and 23) are the mostoutwardly extending structures in the direction transverse to thelongitudinal axis of the container. Thus, adjacent containers in ashipping configuration or on a filling line will contact at the bumpers(16 and 23) rather than at the sidewalls 14, thereby preventing damageto the labeling. An upper peripheral groove 17 is positioned between theupper label bumper 16 and the sidewalls 14. Similarly, a lowerperipheral groove 21 is positioned between the lower label bumper 23 andthe sidewalls 14.

The upper and lower label bumpers (16 and 23) and upper and lowerperipheral grooves (17 and 21) are arranged such that the front and backlabel panel areas are inset from the label bumpers by a greater amountthan the side label panel areas. The greater inset of the front and backlabel panel areas allows a consumer to lift the container by grippingthe front and back label panel areas between their thumb and fingers,because the label bumper acts as a stop to prevent the container fromslipping out of the consumer's hand. At the same time, the lesser insetof the side panels allows the front and back labels to present thelargest possible surface area to consumers, thereby increasing thecommercial desirability of the container.

In addition, because the label panel areas of the sidewalls can be usedas a grip, there is no need to provide a grip portion at the top of thecontainer. As noted above, in conventional containers, such grip areasor handles may take up substantial portions of the top of the container,which may necessitate moving the label area toward the bottom of thecontainer, which is commercially undesirable. By contrast, the containerdescribed herein has a label area that is more centrally positioned inelevation, which may be described in terms of the elevation of thebottom of the sidewalls 14 (which provide the label panel areas)relative to the overall height of the container. In one embodiment, theratio of the elevation of the bottom of the label panels (sidewalls 14)to the height of the container (as measured from the standing edge 26 tothe top edge of the finish 2) is between about 0.1 and about 0.4 and ispreferably about 0.2.

The minimum inset of the front and back label panels may be determinedbased on such factors as the minimum inset necessary to allow theconsumer to stably grip the container, which may in turn depend on theoverall dimensions and weight of the container when filled. For example,a large capacity container will be heavier when filled and therefore mayrequire a greater inset of the front and back label panels. The maximumfront and back label panel inset may depend on such factors as theperformance of the container under top load conditions, i.e., when aforce is applied to the top of the container. If the inset of the frontand back label panels is too great, then the container may deform in thearea near the inset at an unacceptably low top load force.

As noted above, it is generally desirable to have a minimal inset on theside label panels, so as to maintain the greatest possible surface areaon the front and back label panels. The minimum inset of the side labelpanels may be determined based on the minimum distance necessary toprevent the label on the side label panel areas from contacting adjacentcontainers in a shipping configuration or on a filling line. Although, aside inset distance of zero may be used.

Based on the criteria discussed above, in one embodiment, the front andback label panel areas may be inset, for example, by a distance of about0.180 inches from the upper label bumper 16 (measured in the transversedirection), while the side label panel areas may be inset by a distanceof about 0.050 inches. In other embodiments, the front and back insetdistance may be in a range of about 0.08 inches to about 0.250 inches,which corresponds to between about 2% and about 7% of the depth of thecontainer in the front-to-back transverse distance, as measured betweenthe front and back edge of the upper label bumper 16. As noted above,the side label panels are inset by a smaller distance than the front andback label panel areas (and may have a zero inset). The ratio of theside inset distance to the front and back inset distance may be betweenzero and about 0.5. In some embodiments the front label panel and theback label panel may be inset by different distances, in which casethese distances may be specified separately. Typically, the two sidelabel panels will each be inset by the same distance, but this is not anecessity

FIGS. 4A and 4B, respectively, show a cross-section of the body portion6 of the container between ribs 19 and through a rib 19. As discussedabove, each rib 19 has separate portions that end in the corner portionsof the sidewalls 14, separated by a gap (y_(RG)). In one embodiment, thegaps, y_(RG), that separates the portions of each rib is between 0% andabout 7% of the circumference of the container measured at the rib. Inthe case of a zero-width gap, the rib portions would meet at the corner,but would have zero depth at that point and thus would still allowhinge-like bending to occur at the corner. As can be seen in FIGS. 4Aand 4B, the sidewalls 14 of the container may be outwardly convex tohelp fight the tendency of the sidewalls 14 to pull in and becomeconcave in response to negative pressure in the container, such astypically arises in the hot-filling process. This in turn can helpprevent the problems that arise in the labeling process in attempting toapply pressure-sensitive labels to concave surfaces.

FIGS. 5 and 6 show bottom views of the rectangular container 10. Asnoted above, the base portion 8 has a tapered heel portion 22 and areentrant portion 32 that extends inwardly and upwardly into thecontainer. The substantially planar standing edge 26 upon which thecontainer 10 rests surrounds the reentrant portion 32. As shown in FIG.6, in one embodiment, the heel may have indented portions at thecorners, which are most pronounced at the bottom of the container andgradually become shallower with increasing elevation until the indentedportions merge with the surface of the container at or near the top ofthe base portion 8. Thus, the lower bumper 23, which is located at thetop of the base portion 8, has the desired rectangular shape withoutindentations.

As noted above, the container 10 may be formed by a blow moldingprocess. In such processes, a perform made of, for example, PET andhaving a particular shape and thickness is stretched and blown usingpressurized gas, and also possibly mechanical means, within a mold. Theperform assumes the shape of the container, which is the interior shapeof the mold. In the case of rectangular containers, the bottom cornersof the container are relatively weaker, because the corners arestretched the furthest and therefore are thinner than other parts of thecontainer. The indented portions of the heel 22 help to reduce thedistance that the corners must be blown from the perform and thereforeresult in thicker and stronger corners. Also, the indented portions alsohelp reduce the possibility of damage to the container during handling,because they help reduce the amount of protrusion of the corners.

The progressively decreasing depth of the indented portions, in thedirection away from the standing edge 26, is shown in thecross-sectional views of FIGS. 8A-8D, which are taken at differentelevations. The shape of the indented portions of the heel can also beseen in FIG. 6. The progressively decreasing depth of the indentedportions may be quantified as shown in FIG. 9, which is across-sectional view of the heel 8. In one embodiment, the ratio of thecorner relief depth (d_(CRD)) to the corner relief width (d_(CRW)) isbetween 0 and about 0.5, as shown in the following equation:

$0.0 \leq \frac{d_{CRD}}{d_{CRW}} \leq {{about}\mspace{14mu} 0.5}$

The particular values of this ratio may be varied along the baseelevation in order to achieve a desired indentation contour, which willbe based on such factors as the height of the base and the maximumdesired corner relief depth desired at the standing edge (which in turndepends on factors such as the standing stability of the bottle). Also,the ratio is higher at the bottom of the bottle, because this is themost difficult part of the container to blow in the blow molding processdue to the height of the reentrant portion 32 of the base portion 8 (seeFIG. 6).

Alternatively, as further shown in FIG. 9, the shape of the indentedportion may be quantified in terms of corner relief radius (d_(CRR)) andthe maximum corner distance (d_(MCD)) is between about 60% and about95%., as shown by the following equation:

${{about}\mspace{14mu} 0.55} \leq \frac{d_{CRR}}{d_{MCD}} \leq {{about}\mspace{14mu} 0.9}$

As shown in FIG. 9, the corner relief radius (d_(CRR)) is measured fromthe center of the container to the closest tangent point on the indentedcorner, and the maximum corner distance (d_(MCD)) is measured from thecenter of the container to the squared-off corner of the container,i.e., the point at which perpendicular lines tangent to the front (orback) and side of the container meet. The maximum corner distance(d_(MCD)) may be obtained from the following equation:

$d_{MCD} = \sqrt{( {( \frac{d_{depth}}{2} )^{2} + ( \frac{d_{width}}{2} )^{2}} )}$

where d_(depth) represents depth of the container and d_(width)represents width of the container.

The present invention is illustrated with respect to a preferredembodiment, but the present invention is not limited to the particularstructure described in the preferred embodiment of rectangular container10. It is understood that persons familiar with container technologywill recognize additional advantages and features that flow from thepresent disclosure, and the present invention encompasses suchadditional advantages and features such that the scope of the inventionis limited only by the claims.

1. A rectangular plastic container formed by blow molding, the containercomprising: an upper portion having a finish at the top for receiving aclosure; an upper label bumper extending around a periphery of thecontainer at a bottom of the upper portion; a base portion having a heelthat curves inward to meet a standing edge at a bottom of the container;a lower label bumper extending around the periphery of the container ata top of the base portion; and a body portion disposed between the upperportion and the base portion, the body portion including front, back,and side label panel areas meeting at rounded corner regions of the bodyportion, the label panels each having a plurality of horizontal ribs,each horizontal rib having four portions separated by gaps, such thateach of the four portions extends into the corner regions of the bodyportion, wherein the front and the back label panel areas are inset fromthe upper bumper by a distance, d_(FI), which is greater than an insetdistance, d_(SI), of the side label panel areas with respect to theupper bumper.
 2. The rectangular plastic container of claim 1, wherein aratio of the inset distance d_(SI) of the side label panel areas to theinset distance d_(FI) of the front and back label panel area is between0 and about 0.5.
 3. The rectangular plastic container of claim 1,wherein a ratio of the inset distance d_(SI) of the side label panelareas to the inset distance d_(FI) of the front and back label panelarea is between about 0.2 and about 0.4.
 4. The rectangular plasticcontainer of claim 1, wherein the front and back label panels areoutwardly convex.
 5. The rectangular plastic container of claim 4,wherein the side label panels are outwardly convex.
 6. The rectangularplastic container of claim 1, wherein the heel comprises indentedportions at corners thereof, the indented portions having a depth thatgradually decreases with increasing elevation, so that the indentedportions merge with the surface of the base at a top portion of thebase.
 7. The rectangular plastic container of claim 6, wherein a ratioof a depth of each of the indented portions to a width of each of theindented portion is between 0 and about 0.5.
 8. The rectangular plasticcontainer of claim 6, wherein, for each of the indented portions, ineach plane of elevation, a ratio of a corner relief radius (d_(CRR)) toa maximum corner distance (d_(MCD)) is between about 0.55 and about 0.9,where the maximum corner distance (d_(MCD)) is given by:$d_{MCD} = \sqrt{( {( \frac{d_{depth}}{2} )^{2} + ( \frac{d_{width}}{2} )^{2}} )}$where d_(depth) is a maximum depth of the container in the plane ofelevation and d_(width) is a maximum width of the container in the planeof elevation.
 9. The rectangular plastic container of claim 1, wherein,for each rib, the gap y_(RG) between the portions of the rib is between0% and about 7% of the circumference of the container at the elevationof the rib.
 10. The rectangular plastic container of claim 1, wherein aratio of an elevation of the bottom of the label panels to the height ofthe container measured from the standing edge to the top edge of thefinish is between about 0.1 and about 0.4
 11. The rectangular plasticcontainer of claim 1, wherein a ratio of an elevation of the bottom ofthe label panels to the height of the container measured from thestanding edge to the top edge of the finish is about 0.2.
 12. Arectangular plastic container formed by blow molding, the containercomprising: an upper portion having a finish at the top for receiving aclosure; an upper label bumper extending around a periphery of thecontainer at a bottom of the upper portion; a base portion having a heelthat curves inward to meet a standing edge at a bottom of the container;a lower label bumper extending around the periphery of the container ata top of the base portion; and a body portion disposed between the upperportion and the base portion, the body portion including front, back,and side label panel areas, wherein the heel comprises indented portionsat corners thereof, the indented portions having a depth that graduallydecreases with increasing elevation, so that the indented portions mergewith the surface of the base at a top portion of the base.
 13. Therectangular plastic container of claim 12, wherein a ratio of a depth ofeach of the indented portions to a width of each of the indented portionis between 0 and about 0.5.
 14. The rectangular plastic container ofclaim 12, wherein, for each of the indented portions, in each plane ofelevation, a ratio of a corner relief radius (d_(CRR)) to a maximumcorner distance (d_(MCD)) is between about 0.55 and about 0.9, where themaximum corner distance (d_(MCD)) is given by:$d_{MCD} = \sqrt{( {( \frac{d_{depth}}{2} )^{2} + ( \frac{d_{width}}{2} )^{2}} )}$where d_(depth) is a maximum depth of the container in the plane ofelevation and d_(width) is a maximum width of the container in the planeof elevation.
 15. A rectangular plastic container formed by blowmolding, the container comprising: an upper portion having a finish atthe top for receiving a closure; an upper label bumper extending arounda periphery of the container at a bottom of the upper portion; a baseportion having a heel that curves inward to meet a standing edge at abottom of the container; a lower label bumper extending around theperiphery of the container at a top of the base portion; and a bodyportion disposed between the upper portion and the base portion, thebody portion including front, back, and side label panel areas meetingat rounded corner regions of the body portion, the label panels eachhaving a plurality of horizontal ribs, each horizontal rib having fourportions separated by gaps, such that each of the four portions extendsinto the corner regions of the body portion, wherein, for each rib, thegap y_(RG) between the portions of the rib is between 0% and about 7% ofthe circumference of the container at the elevation of the rib.